The United States is initiating a closed-door negotiation that could open up new areas to whale hunting for the first time in decades, part of an attempt to end a long-standing impasse over whaling limits with Japan, the world's most avid whaling nation.

The tentative plan, outlined in documents obtained by The Washington Post, seeks to achieve a breakthrough in the dispute that has raged since the International Whaling Commission voted in 1986 to ban commercial whaling. Faced with the reality that Japan and its allies have continued to hunt whales and have succeeded in blocking new conservation efforts, commission Chairman William Hogarth -- an appointee of President George W. Bush -- has been trying this weekend in Hawaii to craft a pact that would permit a new type of "coastal whaling" in exchange for a commitment by Japan to scale back its "scientific" whale hunts.

The proposal is running into stiff opposition from whaling opponents, however.

In recent years, the whaling commission, which requires a supermajority vote to take action, has been deadlocked between the anti- and pro-whaling camps. Rather than setting a clear direction for conserving and managing whale populations worldwide, its meetings have become contentious donnybrooks in which the two sides have competed for influence while little changed.

Worldwide, three countries -- Japan, Iceland and Norway -- continue to hunt whales, either in the name of research or, in Norway's case, under a commercial exception established more than 20 years ago.

The draft proposal, which does not specify how many whales could be killed under the plan, would allow Japan to engage in "coastal whaling" off its shores in exchange for a cut in the number of Antarctic minke whales it takes each year in the Southern Ocean. Several anti-whaling nations have pushed for the creation of a whale sanctuary in the Southern Ocean, the site of the current whale hunt. The coastal whaling provision would apply only to Japanese coastal waters, and it is unclear whether it could be expanded.

In an interview, Hogarth said he knew it would be controversial to condone a new form of whaling, but he argued that it probably is essential to reach an agreement with Japan.

"Even though we might not like this specific aspect, it's better than what we have now, the status quo," he said. "Everyone would like to see that there are less whales killed."

Joji Morishita, Japan's chief negotiator on the commission, said in an e-mail that the outcome of the negotiations could determine whether the international body will continue to function.

"It's decision time," he said. "Very important, very serious decisions need to be taken. It is a critical time for this organization. The IWC could still collapse."

Scientists and environmentalists questioned the proposal, noting that it could increase pressure on small coastal whale stocks without ending the whaling Japan has conducted for years. Japan has begun taking more whales in recent years under the science designation, killing 872 in 2007, compared with 540 in 1997. In addition, Japan reported that in 2007 it accidentally killed 156 minke whales off its coast as bycatch. Korea -- which no longer intentionally hunts whales -- caught 80 coastal minkes as bycatch and identified 14 others as illegally killed.